The charges follow an investigation by the Independent Police Complaints Commission (IPCC).

It is alleged the 22-year-old victim's head was smashed off a wall while he was in police custody last November.

His parents Jimmy and Colette say their son couldn't recognise his own family or the area in Sunderland where he has lived all his life as a result of the head injuries.

Sgt Flasby, 49, who has been suspended since the incident, is due before Sunderland magistrates on June 28. The IPCC has been investigating the incident which took place in the early hours of November 20, after Gavin was taken into custody when dad Jimmy, 43, found him asleep and drunk in a garden near their home.

Mum Colette, 45, called an ambulance after he started choking, but paramedics called police after he became abusive.

IPCC spokesman Ian Christon said: "The IPCC has been advised that an officer will be summonsed to appear before the court on suspicion of committing common assault."